Abstract: In Shanghai land area,many ancient river beds developed in the Quaternary period.The ancient river channel beds since late Pleistocene have substantial effects on construction.Based on large amount of drillhole and test datum,this paper presents the genesis,distribution,and sediment characters of the ancient river channels in late Pleistocene,Holocene,and present years.This paper further analyzes the effects of ancient river channels on construction,especially underground projects.The results of this paper can be used as the basis of investigation,design,and construction of new projects.